Crash cushion for roadside object

ABSTRACT

A sacrificial crash cushion ( 10 ) for a roadside object (e.g. post, mast or pylon), comprising a body ( 12 ) defining a chamber ( 14 ) containing a sacrificial energy absorber ( 16 ), the chamber ( 14 ) having a central region ( 20 ) and a lateral region ( 22, 24 ) on each side thereof, wherein the lateral regions ( 22, 24 ) extend away from the central region ( 20 ) such that the body ( 12 ) has a profile ( 30 ) configured to abut a roadside object, the profile having in each of two spaced-apart locations a contact surface ( 32, 34 ) for contacting a roadside object, with the contact surfaces ( 32, 34 ) facing in different directions.

The present invention relates to a sacrificial crash cushion for a roadside object, such as a signpost, mast or pylon or the like. The function of the roadside object is not important to the present invention; rather, the present invention is applicable to any roadside object which has sufficient inertia to present a hazard to vulnerable road users (eg motorcyclists, cyclists, and passengers ejected from vehicles during an accident) in collision therewith.

A roadside object such as a signpost or lamppost may be a serious hazard to a vehicle's occupant(s) during an accident, particularly if the vehicle leaves the road and collides (e.g. head-on) with the roadside object. One way of reducing the risk of serious injury to a vehicle's occupant(s) is to provide crash cushion barriers in front of the roadside object, either to prevent a vehicle from striking the roadside object or reduce the speed with which the vehicle strikes the roadside object. U.S. Pat. No. 4,101,115 discloses a disposable unit which is mounted in front of a concrete abutment, signpost, guard rail or the like to prevent a moving vehicle from annihilation should it strike the abutment, etc. The crash cushion comprises a container, filled with a compressible mixture of cemented vermiculite, which is ground-anchored using cables. Another way of reducing the risk of serious injury to a vehicle's occupant(s) is to (re)design the roadside objects as sacrificial energy-absorbing structures in their own right so less impact energy is absorbed by the vehicle during a collision. However, it may not always be possible to design the roadside object in such a way.

The present applicant has appreciated the need for an improved crash cushion for roadside objects to help protect the most vulnerable road users (eg motorcyclists, cyclists, and passengers ejected from vehicles during an accident) in collision therewith.

In accordance with one aspect of the present invention, there is provided a sacrificial crash cushion for a roadside object (e.g. post, mast or pylon), comprising a body defining a chamber containing a sacrificial energy absorber, the chamber having a central region and a lateral region on each side thereof, wherein the lateral regions extend away from the central region such that the body has a profile configured to abut a roadside object, the profile having in each of two spaced-apart locations a contact surface for contacting a roadside object, with the contact surfaces facing in different directions.

The resulting sacrificial crash cushion is configured to be fitted to, and at least partially around, the base of a roadside object. This obviates the need for the crash cushion to be anchored direct to the ground. Furthermore, by having a profile which abuts two surfaces of the roadside object which face in different directions, but at least partially towards one another, the sacrificial crash cushion will remain between the roadside object and a person during impact and not be knocked out of the way by the person's incident momentum.

The contact surfaces of the two spaced-apart locations may face in two directions spaced by an angle of between 45° and 135°. In one arrangement, the angle may be about 90°. The body may have a substantially “L”- or “C”-shaped profile or footprint. An “L”-shaped profile or footprint may be suited to roadside objects with a square cross-section (e.g. masts and pylons) and a “C”-shaped profile or footprint may be suited to roadside objects with a circular cross-section (e.g. lampposts).

The central region of the chamber may have an arcuate cross-section in a horizontal plane, such that in use the body has at least in part a curved outer peripheral wall (which in use faces away from its roadside object). It is believed the curved outer peripheral wall will exhibit more uniform deformation characteristics to impacts from different directions. Furthermore, the absence of a “sharp” transition from one lateral region to the other may help to avoid localized stress concentrations during an impact which could lead to premature failure of the sacrificial energy absorber.

The sacrificial energy absorber may comprise at least one layer of a sheet-form structure which extends from the central region to at least one of the lateral regions of the chamber. The sheet-form structure may even extend from one lateral region of the chamber to the other. The sheet-form structure may comprise a honeycomb structure, possibly a honeycomb structure as described in International application WO98/06553, the entire contents of which are incorporated herein by reference. Alternatively, or additionally, the sacrificial member may comprise a press load (or egg box) structure, possibly as described in International application WO00/31434, the entire contents of which are incorporated herein by reference. The sheet-form structure may define a notional median plane which in use is arranged substantially vertically. The median plane may be curved and may have a footprint following the outline of a front or rear face of the body.

The body may comprise at least one opening for receiving a strap to strap the sacrificial crash cushion to a roadside object. For example, one opening may be provided adjacent each lateral region of the chamber. Alternatively, or additionally, the sacrificial crash cushion may further comprise an anchor for securing the body to a roadside object. The anchor may comprise a clamping member, and means for adjusting the position of the clamping member relative to the body. For example, the position adjusting means may comprise a threaded rod part and a corresponding aperture part, configured such that rotation of one part relative to the other adjusts the position of the clamping member relative to the body. With such an arrangement, the sacrificial crash cushion may be clamped in position, against a roadside object with at least a part of the latter between the clamping member and the body.

The sacrificial energy absorber may be configured to be “person-friendly”, in other words it may be configured to deform when exposed to a threshold force level which would be generated by an average person hitting the sacrificial energy absorber head-on at a predetermined speed, such as below 30 mph, or even below 20 mph, or possibly even below 10 mph. In this way, the sacrificial energy absorber may start to deform (and hence start to absorb impact energy) before fatal and even serious injuries are inflicted on a vulnerable road user colliding with therewith. Such functionality may be achieved despite the fact that the body and/or sacrificial energy absorber may be non-resilient (eg having a rigid plastic construction).

In accordance with another aspect of the present invention, there is provided a method of protecting a vulnerable road user in collision with a roadside object, comprising: providing a sacrificial crash cushion in accordance with the first aspect of the present invention (or embodiments thereof); and securing the sacrificial crash cushion to the roadside object.

In accordance with yet another aspect of the present invention, there is provided a highway safety assembly, comprising a roadside object and a sacrificial crash cushion in accordance with the first aspect of the present invention (or embodiments thereof), the sacrificial crash cushion being secured to the roadside object to face in the general direction of oncoming traffic travelling along the road adjacent thereto.

An embodiment of the invention will now be described by way of example, and with reference to the accompanying figures in which:

FIG. 1 is a perspective view of a sacrificial crash cushion embodying the invention;

FIG. 2 is a cut-away perspective view of the sacrificial crash cushion of FIG. 1 showing a sacrificial energy absorber housed therein;

FIG. 3 is a perspective view of the sacrificial energy absorber of FIG. 2; and

FIG. 4 is a schematic sectional view of part of the sacrificial crash cushion of FIG. 1, showing anchor detail.

FIGS. 1 and 2 illustrate a sacrificial crash cushion 10 embodying the present invention. The sacrificial crash cushion 10 has an injection moulded body 12 defining a chamber 14 housing a sacrificial energy absorber 16 (shown fully in FIG. 3). The chamber 14 has a central region 20 and two lateral regions 22, 24, one on each side of the central region 20. The lateral regions 22, 24 extend away from the central region 20 such that the body 12 has a profile 30 configured to abut a roadside object 40 (shown in phantom lines). The profile 30 has two spaced-apart contact surfaces 32, 34 which face in different directions. The contact surfaces 32, 34 are configured to abut adjacent sides of a roadside object in the form of a square section mast. Thus, the surfaces 32, 34 are angularly spaced by about 90°.

The central region 20 of the chamber 14 has an arcuate cross-section in a horizontal plane (i.e. the central region 20 has a footprint shaped like a truncated quadrant of a circle). In this way, the body 12 has at least in part a curved outer periphery 36 which faces away from the roadside object 40. The central region 20 includes an arcuate step 38 to avoid a sharp transition from one lateral region to the other adjacent the roadside object 40. The sacrificial energy absorber 16 comprises layers of a sheet-form structure 50, some of which extend from one lateral region 22 through the central region 20 to the other lateral region 24. The sheet-form structure 50 has the egg-box shape which is disclosed in WO00/31434, the entire contents of which are incorporated by reference. At least one of the sheet-form structures 50 has a notional median plane 52 which is aligned vertically and curves through the chamber 16 in sympathy with curvature of a front wall 54 of the body 12. Adjacent layers of sheet-form structure 50 are separated by stiff sheet material 56 to help avoid localised stress concentrations in the sacrificial energy absorber 16.

FIG. 4 shows an anchor 60 for securing the body 12 to a roadside object 62. The anchor 60 comprises a clamping member 64 such as a bar or plate and means 66 for adjusting the position of the clamping member 64 relative to the body 12. The position adjusting means 66 includes a bolt 68 with a threaded shaft 70 which engages a corresponding aperture 72 in the body 12. Rotation of the bolt 68 relative to the aperture 72 varies the spacing between the clamping member 64 and body 12 enabling at least part of the roadside object 62 to be trapped therebetween.

The body 12 may also have integral openings (not shown) for receiving a strap to strap the sacrificial crash cushion 10 to the roadside object 62. 

1. A sacrificial crash cushion for a roadside object (e.g. post, mast or pylon), comprising a body defining a chamber containing a sacrificial energy absorber, the chamber having a central region and a lateral region on each side thereof, wherein the lateral regions extend away from the central region such that the body has a profile configured to abut a roadside object, the profile having in each of two spaced-apart locations a contact surface for contacting a roadside object, with the contact surfaces facing in different directions, characterised in that the sacrificial crash cushion is configured to prevent during a collision therewith serious injury to vulnerable road users selected from motorcyclists, cyclists and passengers ejected from vehicles during an accident, with the sacrificial energy absorber being configured to deform and absorb impact energy when exposed to a threshold force level which would be generated by an average person hitting the sacrificial energy absorber head-on at a predetermined speed below 30 mph.
 2. A sacrificial crash cushion according to claim 1, in which the contact surfaces of the two spaced-apart locations face in two directions spaced by an angle of between 45° and 135°.
 3. A sacrificial crash cushion according to claim 2, in which the body has a substantially “L”- or “C”-shaped profile or footprint.
 4. A sacrificial crash cushion according to claim 1, in which the central region has an arcuate cross-section in a horizontal plane.
 5. A sacrificial crash cushion according to claim 1, in which the sacrificial energy absorber comprises at least one layer of a sheet-form structure which extends from the central region to at least one of the lateral regions.
 6. A sacrificial crash cushion according to claim 5, in which the sheet-form structure defines a notional median plane which in use is arranged vertically in the chamber.
 7. A sacrificial crash cushion according to claim 5, in which the notional median plane is curved, at least between the central region and one lateral region.
 8. A sacrificial crash cushion according to claim 1, in which the body comprises at least one opening for receiving a strap to strap the sacrificial crash cushion to a roadside object.
 9. A sacrificial crash cushion according to claim 1, further comprising an anchor for securing the body to a roadside object.
 10. A sacrificial crash cushion according to claim 9, in which the anchor comprises a clamping member and means for adjusting the position of the clamping member relative to the body.
 11. A method of protecting a vulnerable road user in collision with a roadside object, comprising: providing a sacrificial crash cushion comprising a body defining a chamber containing a sacrificial energy absorber, the chamber having a central region and a lateral region on each side thereof, wherein the lateral regions extend away from the central region such that the body has a profile configured to abut a roadside object, the profile having in each of two spaced-apart locations a contact surface for contacting a roadside object, with the contact surfaces facing in different directions, characterised in that the sacrificial crash cushion is configured to prevent during a collision therewith serious injury to vulnerable road users selected from motorcyclists, cyclists and passengers ejected from vehicles during an accident, with the sacrificial energy absorber being configured to deform and absorb impact energy when exposed to a threshold force level which would be generated by an average person hitting the sacrificial energy absorber head-on at a predetermined speed below 30 mph; and securing the sacrificial crash cushion to the roadside object.
 12. A highway safety system, comprising: a roadside object and a sacrificial crash cushion comprising a body defining a chamber containing a sacrificial energy absorber, the chamber having a central region and a lateral region on each side thereof, wherein the lateral regions extend away from the central region such that the body has a profile configured to abut a roadside object, the profile having in each of two spaced-apart locations a contact surface for contacting a roadside object, with the contact surfaces facing in different directions, characterised in that the sacrificial crash cushion is configured to prevent during a collision therewith serious injury to vulnerable road users selected from motorcyclists, cyclists and passengers ejected from vehicles during an accident, with the sacrificial energy absorber being configured to deform and absorb impact energy when exposed to a threshold force level which would be generated by an average person hitting the sacrificial energy absorber head-on at a predetermined speed below 30 mph, the sacrificial crash cushion being secured to the roadside object to face in the general direction of oncoming traffic travelling along the road adjacent thereto. 